Field of the Invention
The invention relates to a method of checking the operability of a computing processor by means of a second processor which provides to the first processor a computation rule and a start value. The first processor uses the start value and the computation rule to calculate a result and transfers the result to the second processor, which compares the result with a comparison result.
Methods for monitoring the operability or functionality of a processor are used, in particular, in motor vehicle engineering where the processor controls a safety-related motor vehicle function. For example, the control system for the cruise control or the control system for the throttle valve position is safety-related. The processor which controls the cruise control or the throttle valve position should thus be checked for proper operation.
German published non-prosecuted patent application DE 44 38 714 A1 discloses a method for controlling a drive unit in a vehicle. There, a computation element is provided for carrying out control functions and monitoring functions for power control. The computation element is split into three independent levels. The first level carries out the control of the power, the second level monitors that the control process is carried out, and the third level monitors the operation of the second level.
The second level monitors the control function for controlling the throttle valve by comparing values derived from pre-set values and setting values for the power.